The mid-terms showed more voter fraud than stupidity.
And it was the prototype. They stole a Governor, 2 or 3 Senate seats, 20+ House and countless important down ballot races. They almost got 2 more Governor and 1 more Senate seat. The GOP did nothing.
And (let’s be honest) the Republican mid-term slate in 2018 was somewhat less than inspiring. One can be a big fan of Trump but not loyal enough to the Republican Party as a whole to bother showing up to vote for a Martha McSally. I expect Trump will bring out millions who haven’t voted in years to support him in 2020. Whether they bother to vote for down-ballot GOP candidates is another matter.